The prior art is replete with methods for obtaining billing information in printer systems. For example, U.S. Pat. No. 3,974,363 discloses a programmable billing system for use in a stand-alone reproduction machine. The system provides means for counting reoccurring events and generating a weighted output value proportional to the billing value of the events. It is also known, as disclosed in U.S. Pat. No. 5,305,199, to employ a single tracking system for monitoring inventories of supplies consumed by a network of reprographic machines. Furthermore, U.S. Pat. No. 6,216,113 B1 discloses a network administrator which stores data representing usage of selected printers and a decoder for validating a print job request and a billing account number. The print jobs are verified and billed to an individual or group account number.
A difficulty with the above described techniques is a lack of capability to charge individuals or groups of individuals for usage of the printers on the network. Another difficulty is the lack of a simple method to determine the measurement of the usage of the devices. For example, U.S. Pat. No. 6,216,113 B1 uses various counters and totalizers circuits which count and accumulate device usage information. The system requires at least one counter circuit for every possible operation of the device.